Patent GB-244412-A (GB)
Title: Automatic stopping mechanism for talking machines
IPC: G11B17/02
Filed: 1925-07-25
Abstract: 244,412. Victor Talking Machine Co., (Assignees of Squibb, L. Y.). Dec. 9, 1924. [Convention date]. Starting and stopping.-Relates to gramophones in which automatic stopping-mechanism is provided, comprising a spring-controlled member which is released from a detent, to apply a brake or open a switch in the circuit of a driving motor, when, on the completion of a sound-reproduction from a record, a reverse movement is given to the reproducer. According to the invention, provision is made whereby the parts which effect the release of the stop member are not in contact with each other during the playing of a record, but are brought into engagement only when the reversal of the movement of the reproducer occurs. In the construction shown in Fig. 1, a brake-pad carrying member 17, provided at 16 on a base-plate, has pivoted thereon a latch member 27 and a rack 35. A spring 44 connects the latch 27 to a detent arm 41 which is pivoted at 40, and so acts that when the parts are in the position shown, a projection 28 on the latch abuts against the end of the detent, and the brake-pad 21 is held off the rim of the turntable. Mounted on the same pivot as the detent 41 is a trip lever 49, 53 (shown separately in Fig. 2.) The arm 49 of this lever is bifurcated at 51, to be engaged by a pin 66 projecting from the tone-arm, while the arm 53 carries with it an arm 56 overlying it. Lugs 58, 59 on the arm 56 form the connection between the parts 53, 56, but allow a little free relative movement. The arm 56 carries a pawl 61, which is adapted under certain conditions to engage the rack 35, and which has a projection 62 lying in a notch 55 in the arm 53. The operation of the mechanism is as follows. Assuming that the parts are in the position shown in Fig. 1, with the machine in operation, the tail 36 of the rack 35 is in contact with the detent 41, and the rack is positioned concentrically with the pivot 40 but out of contact with the pawl 61. When, during the travel of the tone-arm and sound-box across the record, the pin 66 engages the branch 67 of the lever 49, the latter is turned anti-clockwise about its pivot; the arm 56 is moved similarly, and the pawl 61 is carried in a path parallel to but out of contact with the rack 35, being held away therefrom by the engagement of the notch 55 with the lug 62. At the end of the soundreproduction the stylus enters an eccentric groove 11' on the record, and the sound-box is thus given a reverse movement (though any suitable means, other than the eccentric groove may be adopted for this purpose). The direction of turning of the parts 49, 53, 56 is thus reversed, and the pawl 61 is brought into engagement with the rack, causing it to move and shift the detent 41 away from the lug 28 on the latch member 27. Thereupon the spring 44, acting through the part 27, rotates the step-member 17, applying the brake to the turntable. At the same time the rack is carried clear of the pawl 61. The device is reset by means of a lever 30, when the reproducer has been returned to the starting position. Manual release of the brake may also be effected at any time during the sound reproduction by turning the lever 30 anti-clockwise from the position shown in Fig. 1. A modification is described in which the rack, instead of being pivoted on the stop-member, is slidably mounted on a detent lever which corresponds to the member 41 of the construction shown in Fig. 1. Any suitable form of stopping-device other than a brake engaging the turntable may be employed; or instead of a brake a switch for opening and closing the circuit of a driving electromotor may be provided. One construction embodying a switch is described and illustrated in the Specification. In the last-mentioned modification a timing-device, such as that described in Specification 202,959, is also provided for automatically breaking the motor circuit after a determined period, should the mechanism controlled by the tone-arm fail to act and the switch not be operated by hand.